It was a four-stroke cycle gas internal combustion engine with intake, compression, power, and exhaust strokes . one of Otto's more than 25 patents on this engine was later challenged and overturned in order to allow Daimler and Maybach to produce their high speed engine.
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The cycle is characterized by four " strokes ", or straight movements alternately, back and forth, of a piston inside a cylinder : ( 1 ) the intake stroke, ( 2 ) the compression stroke, ( 3 ) the power stroke, and ( 4 ) the exhaust stroke.
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In the single-piston designs, the engine captures the heat lost from the four-stroke Otto cycle or Diesel cycle and uses it to drive an additional power and exhaust stroke of the piston in the same cylinder in an attempt to improve fuel-efficiency and / or assist with engine cooling.
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Four-stroke 4-cylinder engines can be built without a distributor, as in the Citroen ID19 . Two coils are used with one coil firing two of the spark plugs simultaneously, resulting in a wasted spark on the cylinder currently on its exhaust stroke, and the other coil used for the other two cylinders.
